We were waiting for the rest of our group to get planet side, waiting for some long, long, long load screens to finish.
We are not on a pvp server, we did not harass them (we were very tempted), and they did not harass us. We didn't get a chance to pull the boss.

And yes were were still grouping up when they came and downed him in the second instance. My guild will obviously have another opportunity to down him no question, I am posting this because we noticed what they were doing and saw how much of an issue this could create across the server.

I don't think one group should be able to farm the boss in multiple instances.